Those communities are the worst.
Steam has a community from certain part of the globe that are some Neanderthal minded.

If some games do not offer character creation/customization and some do not not like it, it is what it is. And what I'm about to say is kind of comparing apples to oranges. But I remember when you had to accept the randomness of rolling up a character in Dungeon & Dragons (old school). You do have some choices such as character class. But what if you wanted to be a fighter, but the dice roll resulted in a higher intelligence and physically weaker character? That's where the role play comes in. In regards to Rust, how hard is it to accept controlling a fictional character that's physically opposite of what you are?

Why limit it to complexion and genders from planet Tellus?
If they wanted to have easily recognizable avatars without spending six months programming a customization tool, they should just make a genderless humanoid and let people choose colour from a palette.

I really don't get this whole thing of needing to identify with a game avatar to be able to enjoy a game. Seems pretty narcissistic to need a likeness to yourself to enjoy a game.

Have people really lost the imagination to be able to enter someone else's world?

Somehow I don't think Mario became so big due to the large number of overweight Italian plumbers with twins/brothers...

In my opinion, it's not a bad thing or narcistic. People prefer main characters in movies, tv shows, comic books, books, manga, anime, etc to be relatable to 'em or a ideal version of who they want to be. It's the difference between a character being likeable and the character feeling alien to 'em.  People will naturally seek out kindred spirits or/and others they can look up to. It's how we choose our friends for the most part and lovers. Sometime in common to something to relate. Any decent writer will want whoever is reading to either relate to their characters/form bonds or look up to their characters and want to become them. 

Being able to customize a character is the easiest way to please every gamer that plays that game and to where they bond or form some kind of attachment to the character. Personally, I play games like that and the ones like the witcher where you play as a set character with a set storyline.  I like both. The witcher is like reading a book where you're along for the ride. A game like Fallout 4 relies on your imagination to form your own character and story. 

Its kinda stupid auto-creating a character for people. I know I would be pissed if I went to play Dark Souls 3 and it was just like "we randomly made a character for you and you have no say in it". If you are including that kind of character diversity, you should put it in the hands of the players, not RNG.

Don't get me wrong, I'm not against some games having character creation. It's specifically this needing it to be like you physically to be able to relate to it that I find concerning.

Not aiming this at you personally. But I find the lynch mob that seems to start up now when this isnt a feature ridiculous. If a game let's you do it, great. But openly criticising developers for not letting you do it and claiming you can't enjoy/relate to the game or character because you didn't choose how it looked shows really reflects poorly on their attitudes towards other genders, races and sexualities.

On Forza Horizon, it was actually really cool to drive around with a recreation of my own car. Just like it can sometimes be cool to put something resembling a more athletic me into a game. But there seems to be a trend towards expecting this to be the norm in a game, and to be blunt, a Renault Clio reaching around in WipeOut or F1 would be ludicrous.

Expecting to be able to put yourself in every game is a similarly ludicrous expectation. And if you can't relate to someone if they're not your sex, race and sexual orientation is something you need to work on, not something a developer needs to fix for you.